<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../js/vue.js"></script>
</head>
<body>
  <div id="app">
    <p>First name: <input type="text" v-model="firstName"></p>
    <p>Last name: <input type="text" v-model="lastName"></p>
      <p>fullname:{{fullname}}</p>
      <button @click="change">改变fullname</button>
  </div>
<br>
  <script>
    var vm = new Vue({
      el:"#app",
      data:{
           firstName:'',
           lastName:''
       },
       methods:{
        change(){
            this.fullname='Harry Potter';
        }
       },
       computed:{
        fullname:{
            get:function(){
                return this.firstName+' '+this.lastName;
            },
            set:function(newVal){
                var arr=newVal.split(' ');
                this.firstName=arr[0];
                this.lastName=arr[1];
            }
        }
       }
     })
   </script>
</body>
</html>